Fabrication process for photovoltaic cell

Abstract

A photovoltaic strip is physically separated from a semiconductor wafer utilizing physical sawing or other techniques. In accordance with one embodiment, a type of semiconductor wafer is first determined by interrogating the wafer to identify one or more of its optical, thermal, or electrical characteristics. This information regarding substrate type is then communicated to a separation apparatus, which then accomplishes precise physical separation of the substrate into discrete strips. Electrical performance of the strips may be tested prior to their incorporation into an assembled solar cell, where they are coupled to a concentrating element utilizing an elastomer encapsulant.

1. A method of fabricating a solar cell comprising:
 interrogating a semiconductor substrate with a combination of optical, thermal, and electrical techniques to detect at least one characteristic of the substrate; 
 comparing the characteristic to information stored in a database regarding a plurality of substrate types, in order to determine a type of the substrate; and 
 physically separating the semiconductor substrate into one or more photovoltaic strips based upon the substrate type determined, 
 wherein the thermal interrogation comprises:
 applying a potential difference across contacts on the substrate; and 
 detecting resulting ohmic heating of conducting elements. 
 
 
     
     
       2. The method of  claim 1  wherein the optical interrogation comprises scanning a wafer surface to identify a pattern of conducting lines present thereon. 
     
     
       3. The method of  claim 1  wherein the electrical interrogation comprises illuminating a front side of the wafer and detecting at least one of electrical currents and voltages on one surface of the substrate. 
     
     
       4. The method of  claim 1  further comprising incorporating the photovoltaic strip into an assembled solar cell.